Method of applying an abrasion resistant finish onto a pultrusion substrate

ABSTRACT

A lineal product includes a composite pultruded substrate having a solid outer surface, and a multi-layer coating extruded directly onto the outer surface. The coating comprises a solid extruded base layer comprising a first thermoplastic material extruded onto the outer surface, the base layer having a base-layer inner surface in intimate contact with the outer surface and a base-layer outer interface. The coating further comprises a solid extruded outer layer comprising a second thermoplastic material comprising polymethyl methacrylate extruded onto the first thermoplastic material, the solid extruded outer layer having an outer-layer interface in intimate contact with the base-layer outer interface and an outer-layer outer surface, wherein the intimate contact between the base-layer outer interface and the outer-layer interface forms a solid interface between the base layer and the outer layer. The solid extruded outer layer has a hardness of at least 1H pencil hardness.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. 119 (e) of U.S.Provisional Application No. 60/970,073 filed on Sep. 5, 2007, which ishereby incorporated by reference in its entirety.

FIELD

This application generally relates to plastic components and morespecifically to pultruded products.

BACKGROUND

The development of pultruded fiberglass reinforced plastics has evolvedaround the necessity for linear shapes that require high strength toweight ratios and cost effective manufacture of complex lineal shapes.Furthermore, fiberglass reinforced plastics have low thermal expansionthat enables products to have a prolonged working life due to minimizedthermal cycling stress on joints and seals. Applications that call forthe virtues of composites include but are not limited to buildingproducts such as door frames, window frames, exterior trim and exteriorsiding.

With exterior applications comes a need for exterior durability. Also,there is a need for abrasion resistance, especially in dark colors. Itis a known problem for dark colors to show flaws more readily than lightcolors. Light colors have more light scattering that blends in the glarethat reflects from a scratch; whereas, dark colors absorb light aroundthe scratch and reflect light on the edges. The contrast of a lightcolored scratch near a dark base is more perceptible to the human eye.

What is needed is a product that has the strength and low thermalexpansion of pultrusion which also possess the ability to resistblemishes created after manufacture.

SUMMARY

A lineal product includes a substrate having an outer surface, athermoplastic base layer applied to the outer surface, and a secondthermoplastic layer applied over at least a portion of the base layer,the second layer having a hardness of at least 1H pencil hardness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section of an extrusion die used to apply first andsecond layers of thermoplastic to a substrate, in accordance with oneembodiment.

FIG. 1A shows in detail a part of the die of FIG. 1 where the secondlayer of thermoplastic is applied to the base layer of thermoplastic, inaccordance with one embodiment.

FIG. 2 shows a cross section of an extrusion die used to apply first andsecond layers of thermoplastic to a substrate, in accordance with oneembodiment.

FIG. 2A shows in detail a part of the die of FIG. 2 where the two layersof thermoplastic are applied to the pultruded substrate, in accordancewith one embodiment.

FIG. 3 shows a schematic setup for a pultrusion, in accordance with oneembodiment.

FIG. 4 shows a cross section of a pultruded part where first and secondlayers of thermoplastic follow the contours of the pultruded substrate,in accordance with one embodiment.

FIG. 5 shows a cross section of a pultruded part where a base layer ofthermoplastic follows the contour of the pultruded substrate, while asecond layer of thermoplastic follows the contour of the pultrudedsubstrate, but also defines some of the details of the final part, inaccordance with one embodiment.

FIG. 6 shows a cross section of a pultruded part where a base layer ofthermoplastic covers less than the entire surface and a second layer ofthermoplastic covers the entire surface, in accordance with oneembodiment.

FIG. 7 shows a cross section of a pultruded substrate where a base layerof thermoplastic covers the entire surface and a second layer ofthermoplastic covers less than the entire surface, in accordance withone embodiment.

FIG. 8 shows a cross section of a pultruded substrate, in accordancewith one embodiment.

FIG. 9 shows further details of the pultruded substrate of FIG. 8.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that the embodiments may be combined or that otherembodiments may be utilized and that structural changes may be madewithout departing from the spirit and scope of the present invention.The following detailed description is, therefore, not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims and their equivalents.

FIG. 1 shows a cross section of one embodiment of an extrusion die 123,in accordance with one embodiment. In this example, pultruded substrate120 is pulled through the extrusion die 123. A base, first layer ofthermoplastic 121 is forced to the surface of the pultruded substrate120. The pultruded substrate 120 then continues through the extrusiondie 123. Next, a second layer of thermoplastic 122 is forced onto thebase layer of thermoplastic 121. The second layer of thermoplastic 122covers at least a portion of the base layer of thermoplastic 121. Thesecond layer 122 can be an outer layer that provides the proper hardnessto protect the part from showing scratches.

FIG. 1A shows a detail view of FIG. 1. The pultruded substrate 120 istraveling through the extrusion die 123. For example, pultrudedsubstrate 120 can include a fiber reinforced thermoset resin. Thepultruded substrate has the base layer of thermoplastic 121 and thesecond layer of thermoplastic 122 is being forced onto the base layer ofthermoplastic 121.

In one embodiment, the pultruded substrate 120 is coextruded with thebase layer of thermoplastic 121 taking the shape of the pultrudedsubstrate 120 and being approximately 3-5 mils in thickness. Someembodiments include a base layer 121 having a thickness of betweenapproximately 1 mil to 20 mils. After the base layer of thermoplastic121 is applied the second, outer layer of thermoplastic 122 iscoextruded over the base layer of thermoplastic 121, and having athickness of approximately 1-2 mils thick. Some embodiments include asecond layer 122 having a thickness of between approximately 1 mil to 20mils. In some embodiments, the second layer of thermoplastic can besofter or harder than the substrate layer.

For maximum scratch and abrasion resistance the second layer ofthermoplastic 122 can be 5H pencil hardness or harder, for example.Using a second, relatively harder outer layer of thermoplastic 122minimizes the visibility of a scratch or mar thus making a product thatis resistant to blemishes. Some embodiments use a second layer 122having a hardness of 1H pencil hardness or harder; some embodiments usea second layer 122 having a hardness of 2H pencil hardness or harder;some embodiments use a second layer having a hardness of 3H pencilhardness or harder; some embodiments use a second layer having ahardness of 4H pencil hardness or harder. The hardness of the secondlayer 122 is chosen to be hard enough to prevent scratches during normaluse of the pultruded part, whether the pultruded part is used as doortrim, window trim, siding, or other use.

In some embodiments, the pultruded part can include dark colors or lightcolors. For example, substrate 120 can include dark colors and/or lightcolors, base layer 121 can include dark colors and/or light colors, andsecond, outer layer 122 can include a clear coating. In otherembodiments, the second layer 122 can also include dark colors. Usedherein, dark colors refers to any non-clear colored layer and caninclude layers having multiple colors and textures. For example, darkcolors can include light brown, dark brown, black, red, maroon, blue, orother colors. When the pultruded substrate 120 and/or base layer 121include dark colors and the hard outer layer 122 is clear, the finalproduct pultruded part provides for an aesthetic dark product that isscratch resistant due to the hard, clear outer layer. Used herein, clearmeans that the layer is substantially free of pigments such that thelayer is substantially transparent so as to allow the base layer to beseen through the clear layer.

In some embodiments base layer 121 includes a thermoplastic includingfillers and pigments to add color and to make it adhere to the surfaceof the pultruded substrate.

In some embodiments, outer layer 122 includes a thermoplastic andincludes little if any fillers or pigments. The thermoplastic layer 122can include a material such as a high molecular weight polymer such as apolymethyl methacrylate, or a high molecular weight acrylic polymer. Insome embodiments thermoplastic layers 121 or 122 can includethermoplastic polymers such as polyesters, polyethylene, polypropylene,polystyrene, polyvinylchloride, polyphenylene oxide, polysulfones,polyaryl ethers, polyaryl sulfones, polycarbonates, polyurethane,polyacrylates such as polymethyl methacrylate, polymethyl acrylate andpolyacetyls.

FIG. 2 shows a cross section of one embodiment of an extrusion die 133,in accordance with one embodiment. A pultruded substrate 130 is pulledthrough the extrusion die 133. A base layer of thermoplastic 131 isfirst applied onto the pultruded substrate 130. A second layer ofthermoplastic 132 is applied onto the base layer of thermoplastic 131.The second layer of thermoplastic 132 covers the base layer ofthermoplastic 131. Both the base layer of thermoplastic 131 and thesecond layer of thermoplastic 132 are then forced onto the pultrudedsubstrate 130.

FIG. 2A shows a detail view of FIG. 2. The pultruded substrate 130 istraveling through the extrusion die 133. The pultruded substrate 130 hasthe base layer of thermoplastic 131 already applied. The second layer ofthermoplastic 132 is applied to the base layer of thermoplastic 131.Both the base layer of thermoplastic 131 and the second layer ofthermoplastic 132 are forced onto the pultruded substrate 130. Baselayer 130 and second layer 132 can include the same thicknesses andhardness as discussed above for FIGS. 1 and 1A.

FIG. 3 illustrates a pultrusion process, in accordance with oneembodiment. The pultrusion process is used to create fiber reinforcedplastic parts with a constant cross section. The pultrusion processbegins with packages 151 of spooled rovings. A roving is composed ofnumerous amounts of fibers (typically glass fiber). The packages 151 areheld by creels 150. The rovings are guided from the creels 150 through aresin impregnation fixture 152. The rovings are combined with rolls 153of mat, veils, weave, or combination of fabric in the forming fixture154. The formed rovings and fabric enter a curing or pultrusion die 155where the shape of the fiber reinforced composite is determined. Toinstigate cure, the pultrusion die 155 is heated in the range of 100 to700° F. The cured part then enters an extrusion die 156.

In die 156, a first extruder 157 forces a base layer of coating (such asbase layer 121 of FIG. 1) into the extrusion die 156. A second extruder158 forces a second, outer layer of coating (such as second layer 122 ofFIG. 1) into the extrusion die 156. The process of applying the coatingsto the pultruded substrate has been described in FIGS. 1, 1A, 2, and 2A,discussed above. A puller mechanism 159 is the component that drives thepultrusion process. The puller mechanism 159 can either be areciprocating clamp or a continuous type puller. A saw 160 or other typeof fabrication equipment cuts the pultruded part. In addition topultrusion, aluminum extrusion, roll formed steel, and plastic extrusioncan adopt this coating system by persons skilled in the individual art.

FIG. 4 shows one embodiment where a pultruded substrate 170 is coatedwith a base layer of thermoplastic 171 and a second layer ofthermoplastic 172. Both the base layer of thermoplastic 171 and thesecond layer of thermoplastic 172 follow the contours of the pultrudedsubstrate 170. Layers 171 and 172 can be similar to layers 121 and 122,as discussed above.

FIG. 5 shows one embodiment where a pultruded substrate 180 is coatedwith a base layer of thermoplastic 181 and a second layer ofthermoplastic 182. The base layer of thermoplastic 181 follows thecontours of the pultruded substrate 180, while the second layer ofthermoplastic 182 follows some of the contours of the pultrudedsubstrate 180, but also defines some of the details in the pultrudedsubstrate 180. Layers 181 and 182 can be similar to layers 121 and 122,as discussed above.

FIG. 6 shows one embodiment of the invention where a pultruded substrate190 is coated with a base layer of thermoplastic 191 and a second layerof thermoplastic 192. The base layer of thermoplastic 191 covers lessthen the entire surface of the pultruded substrate 190, while the secondlayer of thermoplastic 192 covers the entire surface of the pultrudedsubstrate 190. Layers 191 and 192 can be similar to layers 121 and 122,as discussed above.

FIG. 7 shows one embodiment where a pultruded substrate 200 is coatedwith a base layer of thermoplastic 201 and a second layer ofthermoplastic 202. The base layer of thermoplastic 201 covers the entiresurface of the pultruded substrate 200, while the second layer ofthermoplastic 202 covers less then the entire surface of the pultrudedsubstrate 200. Layers 201 and 202 can be similar to layers 121 and 122,as discussed above.

In various embodiments, the above system can apply to a lineal productincluding: a) pultruded composite; b) extruded aluminum; c) roll formedsteel; or d) extruded plastic. In some embodiments, the lineal productis finished with a die applied multilayer thermoplastic coating. In someembodiments, a thermoplastic base layer follows the contours of thesurface of the profile. In some embodiments, a thermoplastic second,outer layer follows the contours of the surface of the profile. In someembodiments, the thermoplastic second layer defines detail features ofthe profile. In some embodiments, the thermoplastic coating layers coverless then the entire second surface of the profile. In some embodiments,the thermoplastic coating layers cover the entire outer surface of theprofile. In some embodiments, the thermoplastic base layer covers lessthen the entire outer surface of the profile and the thermoplasticsecond layer covers the entire outer surface of the profile. In someembodiments, the thermoplastic base layer covers the entire outersurface of the profile and the thermoplastic second layer covers lessthen the entire outer surface of the profile. In some embodiments, amethod includes applying a multilayer thermoplastic finish to a linealproduct.

In some embodiments, a pultruded part is coextruded with a dark coloredbase layer of thermoplastic taking the shape of the pultruded substrateand being approximately 3-5 mils in thickness. After the base layer ofthermoplastic is applied a second, outer layer of clear thermoplastic isco-extruded over the base layer of thermoplastic, and having a thicknessof approximately 1-2 mils thick. In one embodiment, a base layer ofthermoplastic is simultaneously coextruded with a second layer ofthermoplastic before being drawn onto a pultruded substrate.

In one embodiment, a pultruded part is coextruded with a base layer ofthermoplastic taking the shape of the pultruded substrate substantially3-5 mils in thickness. After the base layer of thermoplastic is applieda second, outer layer of thermoplastic is coextruded over the base layerof thermoplastic in a fashion that defines the final shape or a detailfeature of the part. In some embodiments, the second layer ofthermoplastic can be softer or harder than the substrate layer.

For maximum scratch resistance the second, outer layer of thermoplasticcan be 5H pencil hardness or harder, for example. Using a second, outerlayer of thermoplastic minimizes the visibility of a scratch or mar thusmaking a product that is resistant to blemishes. Some embodiments use asecond layer having a hardness of 1H pencil hardness or harder; someembodiments use a second layer having a hardness of 2H pencil hardnessor harder; some embodiments use a second layer having a hardness of 3Hpencil hardness or harder; some embodiments use a second layer having ahardness of 4H pencil hardness or harder.

FIG. 8 shows a cross section of a pultruded substrate 300, in accordancewith one embodiment. Pultruded substrate 300 is coated with a base layerof thermoplastic 301 and a second layer of thermoplastic 302. Layer 301can be similar to layer 121, as discussed above. In this embodiment,second, outer layer 302 includes a clear thermoplastic having a hardnesssuch as discussed above for layer 122 (e.g., 5H pencil hardness), andadditionally includes a plurality of micro-beads 304 to provide a lowergloss finish than the thermoplastic alone. Moreover, the microbeads 304provide a much better low-angle glare than the outer layer without themicro-beads.

FIG. 9 shows further details of pultruded substrate 300. A plurality ofmicro-beads 304 are homogeneously mixed throughout outer thermoplasticlayer 302. Micro-beads 304 can be small glass, acrylic, or othermaterial particles which are provided in the outer layer 302 at such adensity so as to lower the gloss and low angle glare of the clear outercoating 302. For example, the micro-beads can have a size of about 10microns to about 30 microns and can be provided at about a 10% densityin the outer layer 302. Some embodiments have a micro-bead density ofabout 10% or less in the second layer 302.

Micro-beads 304 can be a cross-linked acrylic micro-bead or a finelyground cross-linked acrylic. The cross-linked microbeads 304 do notdissolve into the base clear acrylic layer 302 during extrusion. Becausethe microbeads 304 do not dissolve, they form a low gloss or texturedsurface when they exit the crosshead extrusion die. The textured surfaceeliminates the low angle (e.g., less than about 10 degrees) mirror likeglare. The use of these beads also eliminates normal fingerprinting(oily fingers leaving a mark on the plastic) and makes a very scratchresistant surface.

The above description is intended to be illustrative, and notrestrictive. Many other embodiments will be apparent to those of skillin the art upon reviewing the above description. The scope of theinvention should, therefore, be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled.

1. A lineal product comprising: a composite pultruded substrate having asolid outer surface; and a multi-layer coating extruded directly ontothe solid outer surface of the pultruded substrate, the coatingcomprising: a solid extruded base layer comprising a first thermoplasticmaterial extruded onto the solid outer surface, the solid extruded baselayer having a base-layer inner surface in intimate contact with thesolid outer surface of the composite pultruded substrate and abase-layer outer interface; and a solid extruded outer layer comprisinga second thermoplastic material comprising polymethyl methacrylateextruded onto the first thermoplastic material of the base layer, thesolid extruded outer layer having an outer-layer interface in intimatecontact with the base-layer outer interface and an outer-layer outersurface, wherein the intimate contact between the base-layer outerinterface and the outer-layer interface forms a solid interface betweenthe solid extruded base layer and the solid extruded outer layer,wherein the solid extruded outer layer has a hardness of at least 1Hpencil hardness.
 2. (canceled)
 3. The lineal product of claim 1, whereinthe first thermoplastic material comprises a colored thermoplastic. 4.The lineal product of claim 1, wherein the second thermoplastic materialcomprises a transparent, substantially transparent, or translucentthermoplastic.
 5. The lineal product of claim 4, wherein the solidextruded outer layer has a hardness of at least 2H pencil hardness. 6.The lineal product of claim 4, wherein the solid extruded outer layerhas a hardness of at least 3H pencil hardness. 7-9. (canceled)
 10. Alineal product comprising: a composite pultruded substrate having asolid outer surface; and a coextruded multi-layer coating coextrudeddirectly onto the solid outer surface of the composite pultrudedsubstrate, the coextruded coating comprising: a solid extruded baselayer comprising a first thermoplastic material extruded directly ontothe solid outer surface, the solid extruded base layer having abase-layer inner surface in intimate contact with the solid outersurface of the composite pultruded substrate and a base-layer outerinterface; and a solid coextruded outer layer comprising a secondthermoplastic material comprising polymethyl methacrylate coextrudedonto the first thermoplastic material of the base layer, the solidcoextruded outer layer having an outer-layer interface in intimatecontact with the base-layer outer interface and an outer-layer outersurface, wherein the intimate contact between the base-layer outerinterface and the outer-layer interface forms a solid interface betweenthe solid extruded base layer and the solid coextruded outer layer,wherein the second layer having a hardness of at least 4H pencilhardness.
 11. The lineal product of claim 10, wherein the solidcoextruded outer layer has a hardness of at least 5H pencil hardness.12. (canceled)
 13. A lineal product comprising: a composite pultrudedsubstrate comprising a fiber-reinforced thermoset resin, the compositepultruded substrate having a solid outer surface; and a coextrudedbilayer coating coextruded directly onto the solid outer surface of thecomposite pultruded substrate, the coextruded bilayer coatingcomprising: a solid extruded base layer comprising a coloredthermoplastic material comprising polymethyl methacrylate extrudeddirectly onto the solid outer surface, the solid extruded base layerhaving a base-layer inner surface in intimate contact with the solidouter surface of the composite pultruded substrate and a base-layerouter interface; and a solid coextruded outer layer comprising a clearthermoplastic material comprising polymethyl methacrylate coextrudedonto the first thermoplastic material of the base layer, the solidcoextruded outer layer having an outer-layer interface in intimatecontact with the base-layer outer interface and an outer-layer outersurface, wherein the intimate contact between the base-layer outerinterface and the outer-layer interface forms a solid interface betweenthe solid extruded base layer and the solid coextruded outer layer,wherein the solid coextruded outer layer has a hardness of at least 1Hpencil hardness.
 14. (canceled)
 15. (canceled)
 16. The lineal product ofclaim 13, wherein the solid coextruded outer layer has a hardness of atleast 4H pencil hardness.
 17. The lineal product of claim 13, whereinthe solid coextruded outer layer has a hardness of at least 5H pencilhardness.
 18. The lineal product of claim 1, wherein the solidcoextruded outer layer includes a plurality of micro-beads.
 19. Thelineal product of claim 1, wherein the first thermoplastic materialcomprises polymethyl methacrylate.
 20. The lineal product of claim 1,wherein one or both of the first thermoplastic material and the secondthermoplastic material consists of polymethyl methacrylate.
 21. Thelineal product of claim 11, wherein the first thermoplastic materialcomprises a colored thermoplastic.
 22. The lineal product of claim 1,wherein the second thermoplastic material comprises a transparent,substantially transparent, or translucent thermoplastic.
 23. The linealproduct of claim 10, wherein the first thermoplastic material comprisespolymethyl methacrylate.
 24. The lineal product of claim 10, wherein oneor both of the first thermoplastic material and the second thermoplasticmaterial consists of polymethyl methacrylate.
 25. The linear product ofclaim 10, wherein the coextruded multi-layer coating is crossheadcoextruded onto the solid outer surface of the composite pultrudedsubstrate.
 26. The lineal product of claim 13, wherein the firstthermoplastic material comprises polymethyl methacrylate.
 27. The linealproduct of claim 13, wherein one or both of the first thermoplasticmaterial and the second thermoplastic material consists of polymethylmethacrylate.